Hi,
I have a DTSMA.7.1 .mkv video that plays the audio 'jerky'. I stripped out the audio, and 'mkvmerged' a DVD audio with a HD video, but it's out-of-sync. Does anyone know how to 're-sync' the audio to the video, so it's in sync?
I have 'Handbrake', 'MKVMerge', and 'River Past Video Cleaner', but I don't see where any of those has a 're-syncing' option.
Thanks!

If it's off by the same amount all the way through you set a delay of the right amount when remuxing. Either that or remove the delay entirely using DelayCut. If the delay gets progressively worse, you may be effectively out of luck. That's the chance you take using audio and video from two different sources.

Is there any difference in frame rates between the original and new audio? Maybe a couple of MediaInfo logs might reveal something?
It sounds like you need a full on editor like Vegas or even Womble or Adobe Audition etc to play with the audio timings.

If it's a offset sync error, where the sync error stays the same though the length of the video, you can play back the video in a player like Media Player Classic and adjust the audio delay or advance there. Then you write down that delay/advance number and use it to add or subtract the start time of the audio in the video. This is fairly easy.

If the sync gradually drifts off, then usually the audio and the video are different lengths. If it's only a small amount, you can sometimes use an audio editor like Audacity to shorten or lengthen the audio until it matches. You will need to demux the audio out, edit it, then mux it back with the video. Still fairly easy.

Unfortunately, sync drift can also be caused because the audio track you have isn't the same as the original video. It may have edits within the video. There is no easy way to fix this except by taking the video apart in small pieces and fixing each of the error parts. Very difficult and time consuming.

Thanks for all the responses. I found that VLC(not my fav player), has options('J', and 'K' keys) to sync-up audio. It doesn't 'fix' the file, just plays it back in sync. I also found that Windows Media Player Classic has an 'audio time shifter' option under internal filters, which will play the file back in sync. Again, this is not a perm fix. The article I found said that you could, after finding out how many ms you wanted to - or +, 'save as' your file, and it would save your video
synced up. I've tried that twice, both times letting it 'save as' for over 15 hours....neither time it worked. It would be nice if Windows Media Player(I have 12), would have this option, but I can't see to find it anywhere...anyone know how to find the 'internal filters'>'audio switcher'>'audio time shift' in WMP12?
Maybe 'save as' would work there?

Yeah, I know what the delay is. Is there a way to remove the delay via 'MKVMerge', or do I have to use Audacity? If I use Audacity, I would have to rip out the audio part(with MKVMerge?), use Audacity to 'edit out' delay at the beginning, then use MKVMerge to merge the video and new audio files together?

Unless your audio is WAV audio, that will require a reencode. So, no, you don't have to, nor should you, use Audacity just for removing a delay. I already told you how to remove the delay completely (hint: DelayCut). Since you extracted the new audio from the DVD, I'll assume you already have it somewhere.